1. Field of the Invention
This invention is in the field of test patterns for optical systems, in particular those patterns from which one may determine such qualities of an optical system as resolution or transfer function.
2. Description of the Prior Art
Various devices and methods are currently desired for testing the quality of optical elements and/or optical paths between such elements. A typical method uses a pattern of opaque shapes on a white or transparent background. Perhaps the most familiar are the various methods used for testing human vision. The simplest of these methods employs various-sized letters on a wall chart. Obviously, patterns more complex than such a wall chart are necessary for more quantitative optical tests. A common pattern for checking resolution is a pattern of opaque lines such as stelliform on a white or transparent background. In order to determine the contrast transfer function (CTF) of an optical system, one needs precise instruments and patterns. The instant invention gives a means of easily determining CTF with a 10-20% error margin.